顿悟中的蔡格尼克效应:左右脑在解题失败与提示信息加工时的活动差异

Zeigarnik effect in Insight problem solving:Hemispheric difference in brain activities following problem solving and during hint presentation

蔡格尼克效应的存在说明人们对于那些未能完成的任务的记忆保持会更好,而利用单侧视野呈现技术对顿悟的研究也表明:人们在问题求解失败后,如提示信息出现较晚,则输入右脑的提示信息会比输入左脑的提示信息更能促成顿悟,提示右脑在未解决问题的保持以及对相关提示信息的处理中发挥重要作用.为了进一步验证上述结果,本研究利用汉字组块破解任务和事件相关诱发电位(ERP)技术,研究和比较了大脑左右两半球在问题求解失败以及关键提示信息呈现两个阶段的活动状况.结果发现,问题求解失败在右半球激发了更大的P150成分,而成功的问题解决却表现出相反的趋势;在提示信息呈现阶段对于P2成分波幅在问题类型(是否成功解决)和偏侧化的交互作用的分析表明,左半球不受问题类型的影响,而右半球的活动则是由不同的问题类型来调控的.上述结果验证了先前的推测,提示问题求解失败会引起右半球对相关问题信息的保持增强,并最终导致右半球对相关提示信息更加敏感.

People tend to exhibit enhanced memory performance for the unfinished tasks relative to the finished ones, which known as the Zeigarnik effect. Consistently, the impasse state in insightful problem solving were believevd to play an important role in maintaining the problem in one＇s mind and in catching the critical clue to overcome the main obstacles. More importantly, through hemi-visual field presentation technology, studies on insight found the keynotes for the unsolved puzzle could be more efficient in catalyzing a breakthrough when presented to the left-visual field （i,e,, the right hemisphere） than to the right-visual field, especially when there was a temporal delay between the disappearance of the puzzle and the presentation of keynotes. This observation implied that the right hemisphere, relative to the left one, might play a more important role in keeping the information of the unsolved problem online and might be more ready in processing the related clue for that problem. In order to testify this hypothesis, we compared the Event-Related Potentials （ERPs） between the solved and unsolved insightful chunk decomposition problems during （a） the moment when the subjects pressed a key to indicate whether or not they could solve the problem by themselves before seeing any external hint, and （b） the moment when subjects were given the hint. The ERPs results showed that, during the moment of subjects＇ confirmation of their successful or unsuccessful problem solving, the unsolved problems were accompanied with a more positive P150 over the right frontal cortex, whereas the solved ones exhibited a more positive P150 over the left side. Consistently, during the moment of hints presentation, the hints to the unsolved problems also elicited a more positive P2 over the right hemisphere, whereas the the hints to the solved problems elicited a more positive P2 over the left side. These results confirmed the hypothesis that, after the failure in insight problem solving, the right hemisphere might be more positive in preserving the unsolved problem in mind and be more responsive to the external hint for problem solving.